This invention relates generally as indicated to a tire building machine and a bead setter and ply turn-up assembly therefor, and more particularly to certain improvements in a tire building machine of the type disclosed in applicant's co-pending application Ser. No. 886,743, filed Mar. 15, 1978, entitled "Modular Tire Building Machine", now U.S. Pat. No. 4,230,517. Such application discloses a unique modular tire building machine that comprises a number of modular packages which can be used interchangeably in single stage, second stage or first stage assemblies. Some of the modular components are particularly useful in the manufacture of larger or truck type tires but can also be used in the automatic or semi-automatic production of smaller passenger size tires. One such modular component is an outboard bead setter mechanism that is supported on a carriage mounted device which device also functions as a transfer for bands, belt and tread assemblies or finished tires and as a retractable two-position idle journal support for the non-driven end of the main shaft of a tire building drum or shaper. Such tire building machine also includes a second or inboard bead setter mechanism opposite the outboard bead setter mechanism supported on the carriage mounted device, and both are adjustable omnidirectionally for accurate bead placement symmetrically about the axis centerline of the shaper or drum and thus the tire being built. Each bead setter mechanism includes a flat ring which constitutes a fixed bead gripping element for the tire bead and a number of bead gripping fingers for holding the bead against the ring. Such tire building machine also employs an expanding bead lock building and shaping mechanism of the general type disclosed in applicant's co-pending application Ser. No. 886,742, filed Mar. 15, 1978, entitled "Tire Building Machine", now U.S. Pat. No. 4,214,939. Such mechanism utilizes an annular elastomeric band or bead lock that is expanded radially beneath the bead properly to center and lock the latter in place for subsequent shaping and ply turn-up and wrapping operations. To effect the latter noted operation, the machine incorporates two expansible cooperating bladders at each end of the drum which, when inflated, will turn the ends of the ply material extending beyond the drum at each end thereof about the bead and firmly press or stitch the same.
While the foregoing tire building machine is suitable for the construction of certain types of tires, some difficulty in wrapping the plies around the bead with no air entrapment may occur with ply materials that are particularly stiff, namely wire, dual cross-ply aramids or cross-woven nylons. The tangential forces required to wrap tightly the stiffer materials around the tire beads generally cannot be obtained with conventional dual bladder turn-up assemblies without requiring high inflation pressures and substantially reducing the useful lives of the bladders. This is particularly a problem in the manufacture of larger or truck type tires. It therefore would be desirable to improve the performance of such tire building machine and other tire building machines in connection with the turning and wrapping of more difficult or stiffer materials, and accordingly it is a principal object of this invention to provide such improved performance in a tire building machine of the foregoing type as well as in other types of tire building machines of the general type described.